Immunolocalisation of desmoglein-1 in equine muzzle skin.
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Animals↗
Biomedical subjects
A Podestà
Publications and source records attributed to A Podestà.
Micro- and nanoscale modification of poly(2-hydroxyethyl methacrylate) hydrogels by AFM lithography and nanoparticle incorporation.
Poly(2-hydroxyethyl methacrylate) (PHEMA) hydrogels are widely used as biomaterials. Due to their unique combination of biocompatibility and good mechanical properties, they have potential as scaffolds for tissue engineering applications. To this purpose, topographic and chemical patterning at the nano- to the mesoscale is crucial in order to favor and to characterize cell adhesion and proliferation. Here we report the characterization of as-prepared and patterned PHEMA hydrogels, produced by conventional radical polymerization in water and dimethylformamide. We have obtained chemical and morphological micro- and nanoscale patterning by atomic force microscopy based lithography. We also demonstrate that it is possible to incorporate carbon nanoparticles in the hydrogel matrix by supersonic cluster beam deposition.
Biocompatible Materials↗
Fractal analysis of sampled profiles: systematic study.
A quantitative evaluation of the influence of sampling on the numerical fractal analysis of experimental profiles is of critical importance. Although this aspect has been widely recognized, a systematic analysis of the sampling influence is still lacking. Here we present the results of a systematic analysis of synthetic self-affine profiles in order to clarify the consequences of the application of a poor sampling (up to 1000 points) typical of scanning probe microscopy for the characterization of real interfaces and surfaces. We interpret our results in terms of a deviation and a dispersion of the measured exponent with respect to the "true" one. Both the deviation and the dispersion have always been disregarded in the experimental literature, and this can be very misleading if results obtained from poorly sampled images are presented. We provide reasonable arguments to assess the universality of these effects and propose an empirical method to take them into account. We show that it is possible to correct the deviation of the measured Hurst exponent from the "true" one and give a reasonable estimate of the dispersion error. The last estimate is particularly important in the experimental results since it is an intrinsic error that depends only on the number of sampling points and can easily overwhelm the statistical error. Finally, we test our empirical method calculating the Hurst exponent for the well-known 1+1 dimensional directed percolation profiles, with a 512-point sampling.
Journal Article↗
Nanofriction behavior of cluster-assembled carbon films.
We have characterized the frictional properties of nanostructured carbon films grown by supersonic cluster beam deposition via an atomic force-friction force microscope (AFM-FFM). The experimental data are discussed on the basis of a modified Amonton's law for friction, stating a linear dependence of friction on load plus an adhesive offset accounting for a finite friction force in the limit of null total applied load. Molecular dynamics simulations of the interaction of the AFM tip with the nanostructured carbon confirm the validity of the friction model used for this system. Experimental results show that the friction coefficient is not influenced by the nanostructure of the films nor by the relative humidity. On the other hand the adhesion coefficient depends on these parameters.
Carbon↗
Epoetin alpha in elective coronary and valve surgery in Jehovah's Witnesses patients. Experience in 45 patients.
BACKGROUND: The religious beliefs of Jehovah's Witnesses who refuse homologous and autologous blood transfusion poses serious problems for surgeons when operating on patients requiring a mean transfusion requirement of =/>2 units of blood. METHODS: After a number of encouraging studies in a randomised sample of patients 2-3 and after the treatment of some Jehovah's Witnesses 1, a group of 45 patients (23 females and 22 males) underwent elective heart surgery between June 1998 and December 2000. The patients, who were all Jehovah's Witnesses, received pre-treatment with epoetin alpha and ferrous sulphate. In the light of recent studies, it was also decided to repeat medullary preconditioning using the same intervals but with a higher dose. The patients underwent surgery involving myocardial revascularisation, mitral and/or aortic valve replacement, associated interventions, valvuloplasty and ascending aortic aneurysms. After obtaining informed and signed consent, the treatment protocol comprised the administration of 140 IU/kg epoetin alpha three times a week for 3 weeks associated with oral ferrous sulphate 3 times a day. Hematochemical levels (hemoglobin, free hemoglobin, hematocrit, ferritin, transferrin, haptoglobin, reticulocytes, iron levels) were monitored from admission to Day Hospital to discharge. RESULTS: No patient in the study required blood transfusion. CONCLUSIONS: The short, medium and long-term follow-up reconfirmed the substantial reliability of this drug linked to the absence of collateral effects.
Administration, Oral↗
Minimally invasive thoracotomy for myocardial revascularisation. A study of 32 cases.
BACKGROUND: This study aimed to evaluate the advantages offered by a myocardial revascularisation technique proposed by Kolessov in 1967: minimally invasive thoracotomy for myocardial revascularisation. The aim was to assess its short and medium-term benefits. During the course of the 1980s, the problems linked to extracorporeal circulation (ECC) and the contraindications for traditional myocardial revascularisation led to a renewed popularity of "beating heart" revascularisation techniques. METHODS: The largest and most extensive series of patients in the literature undergoing myocardial revascularisation during left mini-thoracotomy was reported by Calafiore et al. In this study we report the series treated by our centre which, albeit involving only 32 cases, obtained good results in the short and medium term. This surgical procedure can only be applied to patients presenting monovasal obstructive coronary disease affecting the anterior interventricular artery (IVA) which must not present small calibre, calcified walls or a lateralised or intramyocardial anatomic position. RESULTS: Invasive and non-invasive instrumental tests carried out to control the distal anastomoses of the left internal mammary artery (IMA) did not reveal angulations and/or stenosing tractions before the anastomosis of IMA to a significant extent also for treatment, when isolating IMA, able to obtain the longest possible length and the best mobility. No infection of surgical wounds was reported postoperatively, as sometimes occurs in median longitudinal sternotomy. CONCLUSIONS: The 2-year follow-up showed the resolution of angina in 100% of the patients studied, as well as a satisfactory and rapid renewal of social relations.
Adult↗
PNU-159548, a novel cytotoxic antitumor agent with a low cardiotoxic potential.
PURPOSE: PNU-159548 (4-demethoxy-3'-deamino-3'aziridinyl-4'-methylsulphonyl-daunorubicin), a derivative of the anticancer idarubicin, has a broad spectrum of antitumoral activity in vitro and in vivo attributable to its DNA intercalating and alkylating properties. The present study was conducted to determine the cardiotoxic activity of PNU-159548 relative to doxorubicin in a chronic rat model sensitive to anthracycline-induced cardiomyopathy. METHODS: Young adult male rats were allocated to the following treatment groups: group 1, PNU-159548 vehicle control (colloidal dispersion); group 2, doxorubicin control (saline); groups 3, 4, 5, 6, and 7, PNU-159548 at 0.12, 0.25, 0.50, 0.75, and 1.0 mg/kg, respectively; and group 8, 1.0 mg/kg doxorubicin. Treatments were administered intravenously once weekly for 4 weeks (first sacrifice time) or for 7 weeks (rats killed at weeks 8, 12, 22, 27, or 35). Body weights, organ weights, serum chemistry, hematology, serum troponin-T, and cardiac histopathology were followed throughout the study. RESULTS: Doxorubicin caused irreversible cardiomyopathy evident at week 4 in some rats and progressing in severity in all rats by week 8. There were also marked myelotoxicity, increased liver and kidney weights, testicular atrophy, and about 20% mortality by week 27 in doxorubicin-treated rats. The deaths were attributed to cardiomyopathy and/or nephropathy. PNU-159548 caused a dose-dependent myelotoxicity, with the dose of 0.5 mg/kg per week being equimyelotoxic to 1.0 mg/kg per week doxorubicin. PNU-159548 also caused an increase in liver weight that was reversible and a non-reversible testicular atrophy but, unlike doxorubicin, had no effect on kidney weight. At equimyelotoxic doses, the cardiotoxicity caused by PNU-159548, expressed as the mean total score, was less than one-twentieth of that induced by doxorubicin, and much less than that predicted on the basis of its content of idarubicin, which is in turn markedly less cardiotoxic than doxorubicin. CONCLUSIONS: The novel cytotoxic antitumor derivative, PNU-159548, is significantly less cardiotoxic than doxorubicin at equimyelosuppressive doses. The combination of intercalating and alkylating activities within the same molecule without the cardiotoxic side effects of anthracyclines makes PNU-159548 an excellent candidate for clinical development in oncology.
Animals↗
Quadricuspid aortic valve, parossistyc supraventricular tachycardia and double right kidney: an uncommon association.
Fourteen years after surgery for replacement of the aortic valve, an interesting case previously unreported was brought to our attention. The female patient came to our OP Dept for a routine follow-up: she had been found at surgery to have a quadricuspid aortic valve. Operation dated October 1985. At a careful appraisal of the world-wide literature, we noticed that such an association of pathologies had never been reported before: quadricuspid aortic valve, paroxystical supraventricular tachycardia and right double kidney with double renal pelvis and double proximal ureter. Other anomalies associated with the quadricuspid valve, available in the literature are: patent duct, subvalvular fixed aortic stenosis, ventricular septal defect, hypoplastic anterior mitral leaflet and pulmonary stenosis. The pathologic findings at autopsy of this congenital malformation vary between 0.008% and 0.033%; attention must be turned to the fact that the incidence can be underestimated if not expressly searched for. The first quadricuspid aortic valve was described in 1862 by Balington in an autoptic report and sixty other cases have been reported since. In rare cases this pathology has been diagnosed at angiography. At follow up our patient remains in SR with rare transitory episodes of supraventricular tachycardia.
Abnormalities, Multiple↗
Echocardiographic imaging of the Alfieri type mitral valve repair.
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Aged↗
Atherosclerotic aneurysm of the left main coronary artery. Case report and review of the literature.
Coronary artery aneurysms involve the right coronary artery, the left anterior descending and the left circumflex coronary arteries in descending order of frequency; aneurysms involving the main left coronary artery are extremely rare. Atherosclerosis is the most common cause. Only eleven patients surgically treated with atherosclerotic left main coronary artery aneurysms are reported. We observed the twelfth case of atherosclerotic aneurysm of the left main coronary artery, successfully treated. In a 65-year-old man we found a large aneurysm originating at the distal segment of the left main coronary artery. A thromboendarterectomy was per-formed and was extended back into the left main and down the left anterior descending artery. An aneurysmorrhaphy and a three-vessel coronary artery bypass grafting were also performed. Three years later the patient was asymptomatic. Management of these cases is still controversial and based on anedoctal experience rather than controlled trials. Although surgery has been recommended to prevent complications, there are no available data comparing medical and surgical management. We feel that coronary bypasses should be performed in coronary artery aneurysm patients only when indicated by the severity of stenosis or progressive angina despite medical therapy. It is our opinion that anurysmorraphy should preserve native flow as much as possible.
Aged↗
A CpG-rich RNA and an RNA helicase tightly associated with the DNA demethylation complex are present mainly in dividing chick embryo cells.
In the developing chicken embryo, active DNA demethylation requires both RNA and proteins (Nucleic Acids Res. 25, 2375-2380, 1997; ibid. 25, 4545-4550, 1997, FEBS Lett. 449, 251-254, 1999a). In vitro assays indicate that in the 5- and 12-day-old embryos the highest specific activity of 5-methylcytosine DNA glycosylase is found in the brain, the eyes and the skin. In situ hybridization with antisense CpG-rich RNA tightly associated to the DNA demethylation complex shows a restricted expression pattern only in proliferating tissues such as the neuroepithelia of the brain in 5-day-old embryos. The RNA is absent in differentiated tissues like the skeletal and heart muscle, liver and the crystallin-producing cells in the lens. The CpG-rich RNA is transcribed in a developmental stage-specific rather than in a cell-specific manner. In contrast transcripts of DNA methyltransferase are found in dividing and quiescent cells. In situ hybridization with a probe of a RNA helicase which is also associated with the DNA demethylation complex shows a very similar localization in mitotically active tissues as the CpG-rich RNA. The content of 5-methylcytosine in individual cells was determined with a specific monoclonal antibody and cytometric analysis on tissue sections. The results indicate that proliferating cells have on the average 15% more methylated cytosines than non-dividing cells. This represents roughly 3x10(6) more methylation sites per haploid genome.
Animals↗
Immunological and biochemical evidence that blepharismin is not a prosthetic group.
A polyclonal, multispecific antiserum was raised against a whole 3[(3-cholamidopropyl)-dimethylammonio]-1-propanesulfonate-extract of nonirradiated Blepharisma japonicum cells. It was used to reveal the composition of solutions that were hypothesized to contain the photoreceptor of the ciliate. A Bio-Gel A 1.5 m fine column chromatography of the extract allowed recovery of a single elution peak isolated by recording the 580 nm light absorbance. Fused-rocket immunoelectrophoresis of this material revealed a large number of > 300 kDa coeluted proteins. Blepharismin-rich material with a molecular mass of approximately 50 kDa, consisting of at least nine proteins was obtained when the same extract underwent preparative isoelectric focusing before column chromatography separation. Purification of the pigment obtained from light-exposed cells gave blepharismin-rich material with a molecular weight of approximately 200 kDa. Comparison of the materials obtained under the same conditions, either from the dark-kept or light-irradiated cells, by means of pore-gradient electrophoresis confirmed that proteins present in the two preparations were different. It revealed only a very small amount, if any, of proteins in the chromatography fractions with the highest absorbance at 600 nm. Results are discussed on the basis of the hypothesis that a specific blepharismin-binding protein does not exist in the protozoan.
Animals↗
Photomodulated azoaldolase: a model for light intervention in biological systems?
Azoaldolase is obtained from rabbit muscle aldolase by adding an azo chromophore to a cysteine side chain in each of the four enzyme subunits. The enzyme becomes photosensitive whereas both its catalytic activity and the michaelian kinetics are retained. Chromophore excitation causes E to Z isomerization of the azo bond, and mutually influences the protein-substrate equilibria. The various isomerization and substrate binding equilibria have been investigated under the hypothesis of a cyclic process described by four linked equilibrium constants. The mechanism of the light effect is a continuous adaptation of the specific parameters of the active protein, that is substrate recognition and rate of the catalyzed process. Absorbed light allows the rapid modification of the concentrations of various related molecules, depending on the used frequencies. At present such a mechanism has not been described in photobiology; so azoaldolase can be taken as a model for a possible new mechanism of light regulation of a biological system, based on changes in the molecular recognition by an active protein against its substrate.
Animals↗
Thrombosis of mechanical valve prosthesis: thrombolysis vs surgical treatment. Report of two cases, personal experience and review of the literature.
We report the cases of two patients, previously operated for mitral mechanical valve replacement who developed thrombosis of the prosthesis. The two patients were successfully treated with pharmacological thrombolysis with no recurrence. One patient developed late peripheral embolization most probably due to late mobilisation of a thrombotic fragment. Our experience with surgical management is reported (39 mitral and 5 aortic prosthetic thrombosis from 1982 to 1999 among 89 patients with prosthetic malfunction). Average time interval between surgery and thrombus formation is 26 months (max 204, min 1 month). Rate of mitral thrombosis is 3.9% and aortic 0.25%. Clinical presentation spreads from almost asymptomatic patients to critically ill patients with pulmonary oedema or frank cardiogenic shock. Temporary suspension of anticoagulant therapy (83% in our study group) to rule out minor surgery, appears to be the most frequent cause of thrombosis. Transthoracic or better transoesophageal echo-cardiography and Doppler are by far the most accurate diagnostic tools that can entirely replace angiographic assessment. Operative mortality was 64% in the prosthetic mitral thrombosis and 20% in the aortic one. Thrombolytic treatment may be affected by minor to relevant complications such as peripheral or central embolization but in our experience and according to the literature it seems much less hazardous than re-do surgery. Thrombolytic treatment is advocated for critical patients unless emergency institution of cardio pulmonary bypass is required and/or indicated. Re-do surgery remains indicated for all other cases of prosthetic malfunction.
Adult↗
Anaemia, osteogenesis imperfecta and valve diseases. The preoperative treatment with epoetin-alpha to increase haematocrit and haemoglobin levels in patients with high risk of perioperative bleeding.
The case of a patient with Osteogenesis imperfecta is reported who underwent surgery for mitral valve replacement. Osteogenesis imperfecta is a hereditary disease of the connective tissue, associated with bone fragility, bluish colouring of the sclerae, loss of hearing and dental anomalies. Osteogenesis imperfecta is included in a group of hereditary pathologies with Ehlers-Danlos syndrome, Hurler syndrome, pseudoxanthoma elasticum and Marfan syndrome. In the literature there are few cases of patients with osteogenesis imperfecta operated for mitral valve disease secondary to such disease. The patient also has a positive family history and a severe anaemia: this was treated with epoetin-alpha and ferrous sulphate during the three weeks before surgery. The response to epoietin treatment was good while clinical outcome was poor due to rupture of the posterior ventricular wall in the 12th postoperative hour. The use of epoietin-alpha is discussed.
Anemia↗
Elective coronary and valve surgery without blood transfusion in patients treated with recombinant human erythropoietin (epoetin-alpha).
BACKGROUND: This study evaluates the real effectiveness of epoetin-alpha associated with ferrous sulphate, in reducing blood transfusion in patients undergoing elective open heart surgery not treated with autologous donation. METHODS: Sixty patients had been divided into 2 groups: group A (30 patients) treated with 525 mg ferrous sulphate three time a day per os for 3 weeks; group B (30 patients) treated with epoetin-alpha 10,000 UI twice a week and 525 mg ferrous sulphate 3 times a day. Grouping of patients has been randomized. In both groups hemoglobin, hematocrit, reticulocytes, iron values, ferritine, transferrine, and serological values, have been evaluated sequentially before treatment, before surgery, day of operation, 1st, 2nd, 3rd, 7th postoperative days and at discharge. RESULTS: In group A 86% patients needed blood transfusion (26 out of 30); in group B only 3% of patients needed blood transfusion (1 patient). One year follow up didn't show side effects related to epoetin-alpha. CONCLUSIONS: This study confirms the real effectiveness of epoetin-alpha in reducing the postoperative need for homologous blood transfusion. No side effects due to epoetin-alpha treatment have been proved. The conclusion is drawn that epoetin-alpha can be used as an alternative to blood transfusion or in association with predeposit and in the treatment of basal anemia.
Blood Loss, Surgical↗
Normothermic versus hypothermic perfusion during cardiopulmonary bypass. A randomized study on 132 patients.
BACKGROUND: A prospective randomized trial to compare normothermic CPB with hypothermic CPB has been performed. METHODS: 132 patients undergoing CPB were randomized into two groups: group 1 underwent normothermic CPB and group 2 hypothermic CPB (between 26 and 30 degrees C). RESULTS: Any significant difference was observed between the groups with regard to hospital mortality, blood transfusions, incidence of neurologic deficits and hematocrit, blood hemoglobin levels, platelet counts, plasma concentrations of glutamic-pyruvic transminase, glutamic-oxaloacetic transaminase, creatine kinase, valued at the 12th and 24th postoperative hour and at the 2nd, 3rd, and 4th postoperative day. A significant difference was observed between the groups with regard to tracheal extubation time, discharge time from the intensive care unit and inotropic drug infusion. The normothermic CPB patients group needed shorter time for tracheal extubation and discharge from the intensive care unit: this difference may be ascribed to a shorter inotropic drug infusion. Any increased surgical risks have been observed. CONCLUSIONS: In conclusion, we think that normothermic CPB is favourable because it can reduce costs, it can improve the management of a cardiac surgery unit and it is more comfortable for patients.
Cardiopulmonary Bypass↗
Time-resolved fluoroimmunoassay.
A method is reported to set up a standard competitive TR-FIA. A simple and inexpensive way to prepare reagents and carry out operations is presented as well, with the aim to make it possible to perform a very sensitive analytical procedure in a personalized way within a nondedicated biochemistry laboratory. This protocol is general and can be easily modified with consideration to the analytical target. Once the antibody is available, both its labeling with diethylenetriaminepentaacetic acid dianhydride and Eu3+, and the setting-up of the assay with measurement of europium ion time-resolved fluorescence in a home-made enhancement solution become feasible.
Animals↗